Deg...I think you've over-liberalized (is there such a word???) the copyright
laws stance on copying. The law does not, in fact, SPECIFICALLY allow
copying of works owned by a library. The section (108, I think) which deals
with phonograph recordings does allow a working copy of a recording to be
made, but video and film are not explicitly covered by this section.

In talking to our friend Ivan Bender about this issue, he seems to feel that
making a copy of an at risk videotape or film (i.e. one in danger of biting
the dust) is probably permissable if it can be demonstrated that a reasonable
attempt was made to acquire the work at a fair market price (this is somewhat
similar to the copyright law's stand on OP print materials). I
personally feel a hell of a lot more comfortable doing this with
non-theatrical works than with feature films...

I also believe that copying in advance of need (i.e. making a circulating
or working copy in anticipation of heavy wear, etc.) is a VERY unwise and
legally unsound practice. Similarly, transferring formats (e.g. 3/4" to
1/2") without permission would probably also not hold up in court (unless,
perhaps, it could be demonstrated that the tape being copied was OP and
at risk of falling apart, and that attempts were made to buy a
replacement in the desired format).

Again...most of this falls into the land of unlitigated and unknown...